8.3 Create .gnupg home directories.

If GnuPG is installed on a system with existing user accounts, it is
sometimes required to populate the GnuPG home directory with existing
files. Especially a trustlist.txt and a keybox with some
initial certificates are often desired. This scripts help to do this
by copying all files from /etc/skel/.gnupg to the home
directories of the accounts given on the command line. It takes care
not to overwrite existing GnuPG home directories.